Three-dimensional printing apparatus

ABSTRACT

A three-dimensional printing apparatus including a tank filled with a liquid-state forming material, a platform disposed at the tank, a rotating shaft, a rotating arm, and at least one light source is provided. The rotating shaft is disposed under the tank or above the tank. The rotating arm connects to the rotating shaft such that the rotating arm is driven by the rotating shaft to rotate. The light source disposed on the rotating arm rotates along with the rotating arm and generates light projecting toward the forming material along with the part of the platform moving in the forming material, such that the forming material is solidified in layers and forms a three-dimensional object on the platform.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/164,276 filed on Jan. 27, 2014 which claims thepriority benefit of Taiwan application serial no. 102142348, filed onNov. 20, 2013. The entirety of each of the above-mentioned patentapplications is hereby incorporated by reference herein and made a partof this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a printing apparatus, and particularly relatesto a three-dimensional printing apparatus.

2. Description of Related Art

With the continuous development of science and technology, variousmethods using the additive manufacturing technology to constructthree-dimensional (3-D) models have been proposed. Generally speaking,the additive manufacturing technology converts design data ofthree-dimensional models constructed with computer-aided designsoftware, for example, into a plurality of thin (pseudo-two-dimensional)cross-sectional layers that are continuously stacked.

Currently, several ways to form the thin cross-sectional layers havebeen developed. For example, a movable platform may be disposed in aliquid-state forming material, and an X-Y-Z coordinate systemconstructed according to the design data of the three-dimensional modeldrives a light source to move along the X-Y coordinate and irradiate theliquid-state forming material, so as to solidify the liquid-stateforming material into a desired shape of the cross-sectional layer.Then, as the movable platform moves along the Z-axis, the solidifiedmaterial may be formed into a three-dimensional object throughsolidification in layers.

However, as the current light sources for solidifying materials aremainly laser light sources, a focal length between the laser lightsource and the target of irradiation is required due to the limitationof the optical element required by the laser light source. Therefore, apoint light is used to linearly scan back and forth along the X-Y axisin the liquid-state forming material. Such scanning manner may produce asawtoothed structure in the surface profile when scanning an arc orcurved profile, resulting in an undesirable influence on the appearance.Thus, modifying the undesirable appearance now becomes an importantissue for the artisans of this field.

SUMMARY OF THE INVENTION

The exemplary embodiment provides a three-dimensional printing apparatusthat utilizes a curve of a radiation trace of a movable light source ona radiation plane to make a three-dimensional object printed accordinglyhave a preferable appearance.

The three-dimensional printing apparatus includes a tank, a movableplatform, a rotating shaft, a rotating arm, and at least one lightsource. The tank is filled with a liquid-state forming material. Themovable platform is movably disposed at the tank. A portion of themovable platform is immersed in the liquid-state forming material. Therotating shaft is disposed above or under the tank. The rotating arm isconnected with the rotating shaft, and the rotating arm is driven by therotating shaft to rotate. The light source is disposed on the rotatingarm to rotate with the rotating arm. As the portion of the movableplatform moves in the liquid-state forming material, the light sourceprovides light to irradiate the liquid-state forming material, so as tosolidify a portion of the liquid state forming material in layers andconsequently form a three-dimensional object on the movable platform.

In an exemplary embodiment, a moving trace of the light source is acurve.

In an exemplary embodiment, a moving trace of the light source is atleast a portion a circle.

In an exemplary embodiment, the rotating arm extends along a radialdirection relative to the rotating shaft.

In an exemplary embodiment, the light source is movably disposed on therotating arm.

In an exemplary embodiment, the three-dimensional printing apparatusfurther includes a plurality of light sources disposed on the rotatingarm along a radial direction. At least a portion of the light sourcesselectively provides light to irradiate the liquid-state formingmaterial in the tank.

Accordingly, in the exemplary embodiments, the light source is disposedon the rotating arm, such that the light trace provided by the lightsource on the rotating arm may be a curve on the radiation plane of theliquid-state forming material when the rotating arm rotates relative tothe rotating shaft. Accordingly, the light source is allowed toirradiate the liquid-state forming material in a curved profile andconsequently prevents the sawtoothed structure caused by theback-and-forth linear scanning, making the three-dimensional objectprinted according to the exemplary embodiments have a preferableappearance.

To make the above features and advantages of the exemplary embodimentsmore comprehensible, embodiments accompanied with drawings are describedin detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the exemplary embodiments, and are incorporated in andconstitute a part of this specification. The drawings illustrateembodiments and, together with the description, serve to explain theprinciples of the exemplary embodiments.

FIG. 1 is a schematic view of a three-dimensional printing apparatusaccording to an exemplary embodiment.

FIG. 2 is a schematic view of a three-dimensional printing apparatusaccording to another exemplary embodiment.

FIG. 3 is a top view of a light source of FIG. 1.

FIG. 4 is a schematic view of a three-dimensional object formed with athree-dimensional printing apparatus according to another exemplaryembodiment.

FIG. 5 is a schematic view of a trace of a point light source when acircular profile is formed through linear scanning.

FIG. 6 is a schematic partial view of a three-dimensional printingapparatus according to another exemplary embodiment.

FIG. 7 is a schematic view of one of the trace patterns generated by alight source of FIG. 6.

FIG. 8 is a schematic partial view of a three-dimensional printingapparatus according to yet another exemplary embodiment.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

FIG. 1 is a schematic view of a three-dimensional printing apparatusaccording to an exemplary embodiment. An orthogonal coordinate system isprovided herein for the convenience of describing relevant components.Referring to FIG. 1, a three-dimensional printing apparatus 100 in thisembodiment is adapted to manufacture a three-dimensional object 210based on a three-dimensional model (not shown). The three-dimensionalmodel may be constructed by using computer aided design (CAD) oranimation modeling software. In addition, the three-dimensional model istransversely sliced into a plurality of cross-sections for thethree-dimensional printing apparatus 100 to read the three-dimensionalmodel and manufacture the three-dimensional object 210 according to thecross-sections of the three-dimensional model.

Specifically speaking, the three-dimensional printing apparatus 100 ofthis embodiment includes a light source 110, a movable platform 120, acontrol unit 130, and a tank 140. The tank 140 is configured to befilled with a liquid-state forming material 200, the movable platform120 is configured beside the tank 140, and a portion of the movableplatform 120 is immersed into the liquid-state forming material 200 ofthe tank 140. The light source 110 is movably disposed under the tank140. The control unit 130 is electrically connected with the movableplatform 120 and the light source 110. Here, as the portion of themovable platform 120 moves in the liquid-state forming material 200(from a liquid level of the liquid-state forming material 200 to abottom of the tank 140), the light source 110 provides light toirradiate the liquid-state forming material 200, so as to solidify aportion of the liquid-state forming material 200 in layers, and finallyform the three-dimensional object 210 on a base 122 of the movableplatform 120. In this embodiment, the liquid-state forming material 200is a photosensitive resin, for example, and the light source 110provides ultraviolet light to solidify the liquid-state forming material200. However, the exemplary embodiment is not limited thereto. Materialsand means capable of forming the three-dimensional object are allapplicable to the exemplary embodiment.

In addition, the exemplary embodiment does not limit a position of thelight source relative to the tank. FIG. 2 is a schematic view of athree-dimensional printing apparatus according to another exemplaryembodiment. Differing from the embodiment above, the light source 110 ofthis embodiment is movably disposed above the tank 140 and similarlyprovides a stereolithography process and generates the same effect,except that the movable platform 120 of this embodiment moves from thebottom of the tank 140 to the liquid level of the liquid-state formingmaterial 200. The description provided below is mainly directed to theembodiment shown in FIG. 1.

FIG. 3 is a top view of the light source 110 of FIG. 1. Referring FIGS.1 and 3 simultaneously, it should be noted here that a moving trace D2generated by the light source 110 on an irradiation plane P1 of theliquid-state forming material 200 (i.e. parallel to the X-Y plane) is acurve, and a moving direction D1 of the movable platform 120 (i.e.parallel to the Z-axis) is vertical to the irradiation plane P1. In thisembodiment, the three-dimensional printing apparatus 100 furtherincludes a supporting member 150, a rotating shaft 160, and a rotatingarm 170. In addition, the rotating shaft 160 and the rotating arm 170are disposed in the supporting member 150. The rotating shaft 160provide an axial direction C1, the rotating arm 170 is radiallyconnected with the rotating shaft 160, and the light source 110 isformed of a plurality of light-emitting elements (e.g. light-emittingdiodes (LEDs)) and disposed in the rotating arm 170. Thus, the rotatingarm 170 is driven by the rotating shaft 160 to rotate in the axialdirection C1, such that the light source 110 located on the rotating arm170 may form the curved moving trace D2 on the irradiation plane P1. Itshould be noted that the drawings of the embodiment do not serve tolimit a quantity of the light-emitting elements. Due to limitation onthe drawings, only a number of the light-emitting elements are shown foran illustrative purpose. Generally speaking, during a process ofthree-dimensional printing, it requires the light source 100 to beformed of at least three hundred light-emitting elements within an inchto manufacture the three-dimensional object 210 with a resolution of 300dots per inch (DPI).

Furthermore, the rotating shaft 160 of this embodiment receives acontrol signal of the control unit 130 to adjust the rotating arm 170 toperform a rotating operation (including the rotating direction andangle) in the axial direction C1. The moving trace D2 of the lightsource 110 on the irradiation plane P1 may thus be a curve or at least aportion of a circle. The embodiment is described with a circular traceas a representative of the trace of the light source. However, thedesigner may appropriately make modification based on relevantstructures, such that the trace of the light source on the irradiationplane may be in curves of other forms. With the configuration andmovement of the light source 110, a sawtoothed edge found when forming athree-dimensional object having a curved profile by using a conventionalpoint light to scan the liquid-state forming material 200 through linearscanning as is prevented.

For example, FIG. 4 is a schematic view of a three-dimensional objectformed with a three-dimensional printing apparatus according to anotherexemplary embodiment. In comparison with FIG. 4, FIG. 5 is a schematicview of a trace of a point light source when a circular profile isformed through linear scanning. Referring to FIGS. 3 to 5simultaneously, a three-dimensional object 310 in the embodiment shownin FIG. 4 is manufactured by, for example, the control unit 130simultaneously controlling various light emitting elements to emit ornot emit light while controlling the control arm 170 to rotate in theaxial direction C1 relative to the rotating shaft 160. For example, thelight-emitting elements shown in FIG. 2 are divided into a plurality ofportions L1, L2, and L3. Each of the portions L1, L2, and L3 includes aplurality of light-emitting elements. The control unit 130 is used tocontrol the portions L1 and L3 of the light-emitting elements to emitlight and the the portion L2 not to emit light, so as to solidify theliquid-state forming material 200 in layers and consequently form thethree-dimensional object 310 as concentric cylinders shown in FIG. 4. Inother words, the three-dimensional printing apparatus 100 of thisembodiment is capable of selectively providing light to irradiate theliquid-state forming material 200 with at least a portion of the lightsource 110 (i.e. the portions of light-emitting elements L1 and L3). Itshould be noted that if the conventional point light is used toirradiate the liquid-state forming material, it is then required tolinearly scan back-and-forth on the irradiation plane (i.e. the X-Yplane) to form the concentric cylinders. As shown in FIG. 5, suchscanning manner results in a sawtoothed structure on the circularprofile. Thus, the exemplary embodiment allows the three-dimensionalobjects 210 and 310 manufactured accordingly to have a smooth profileand preferable appearance quality by modifying a moving manner of thelight source.

FIG. 6 is a schematic partial view of a three-dimensional printingapparatus according to another exemplary embodiment for illustrating alight source part of the three-dimensional printing apparatus. FIG. 7 isa schematic view of one of the trace patterns generated by the lightsource of FIG. 6. Referring to FIGS. 6 and 7 at the same time, in thisembodiment, only one light-emitting element is disposed on the rotatingarm 170 as a light source 410 of this embodiment. Also, this embodimentfurther differs from the embodiments above in that the light source 410of this embodiment is movably disposed on the rotating arm 170 relativeto the rotating shaft 160 along a radial direction D3 (as indicated by adouble-arrow sign in the figures). In this way, by using the controlunit 130 (shown in FIG. 1) to control, a moving trace D4 shown in FIG. 7is formed by making use of back-and-forth movements of the light source410 on the rotating arm 170 in addition to rotation of the rotating arm170 relative to the rotating shaft 160. However, the exemplaryembodiment does not limit a pattern of the trace. By controlling themovement of the light source 410, the movement of the rotating arm 170,and a light-emitting frequency of the light source 410 and appropriatelycombining the movement of the light source 410, the movement of therotating arm 170, and the light-emitting frequency of the light source410, the patterns and ranges of the trace patterns of the irradiation ofthe light source 410 on the liquid-state forming material 200 may beincreased. In other words, a light trace of the light source 410 of thisembodiment on the irradiation plane P1 may be considered as a combinedvector of the moving trace D2 and the radial direction D3. Similarly, inan embodiment that is not shown herein, a plurality of movablelight-emitting elements may be disposed on the rotating arm.

FIG. 8 is a schematic partial view of a three-dimensional printingapparatus according to yet another exemplary embodiment for illustratinga light source part of the three-dimensional printing apparatus. Whatdiffers from the embodiments above is that there are two rotating arms570A and 570B in this embodiment, and the rotating arms 570A and 570Bare respectively connected to the rotating shaft 160 and respectivelyextend along the radial direction relative to the rotating shaft 160.Light sources 510A and 510B are respectively disposed on the rotatingarms 570A and 570B. The light source 510A located on the rotating arm570A is formed of a light-emitting element capable of moving back andforth along the rotating arm 570A, whereas the light source 510B locatedon the rotating arm 570B is formed of a plurality of light-emittingelements arranged along the radial direction. In this way, thethree-dimensional printing apparatus is capable of selectively providinglight or increasing types of the moving traces of the light sourceaccording to the control unit 130 (shown in FIG. 1) by making use ofmultiple configurations and movements of the light source. Based on theabove, modifications to the light source disposed on the rotating armwith respect to the quantity, configuration and movement are allapplicable to the exemplary embodiment.

In view of the foregoing, in the embodiments above, thethree-dimensional printing apparatus adjusts the movement of the lightsource under the tank to make the moving trace of the light source onthe irradiation plane a curve, so as to prevent a sawtoothed appearancewhen forming a non-linear profile in the process of solidifying theliquid-state forming material through light radiation. In addition, thedesigner may adjust the quantity, configuration, and movement of thelight source accordingly, so as to increase the types of the light traceof the movable light source on the irradiation plane and expand theapplicable range. Thus, with the relevant structure and configuration ofthe light source, the three-dimensional object printed according to theexemplary embodiment has a preferable appearance.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A three-dimensional printing apparatus,comprising: a tank, filled with a liquid-state forming material; amovable platform, movably disposed at the tank, wherein a portion of themovable platform is immersed in the liquid-state forming material; arotating shaft, corresponding to the tank and rotating about an axis; aleast one light source, disposed on the rotating shaft, rotatingsynchronously and about the axis therewith; and a control unit,electrically connected with the movable platform and the light sourceand controlling a movement of the light source and a light-emittingfrequency of the light source, wherein the light source provides lightto irradiate the liquid-state forming material to solidify at least aportion of the liquid-state forming material in the tank in layers alongwith the portion of the movable platform moving in the liquid-stateforming material to form a three-dimensional object on the movableplatform.
 2. The three-dimensional printing apparatus as claimed inclaim 1, wherein a moving trace of the light source is at least aportion of a circle.
 3. The three-dimensional printing apparatus asclaimed in claim 1, wherein a rotating arm extends along a radialdirection from the rotating shaft, and the rotating arm rotates aboutthe axis with the rotating shaft.
 4. The three-dimensional printingapparatus as claimed in claim 3, wherein the light source is movablydisposed on the rotating arm.
 5. The three-dimensional printingapparatus as claimed in claim 4, wherein a moving trace of the lightsource is a curve.
 6. The three-dimensional printing apparatus asclaimed in claim 1, wherein the rotating shaft is disposed above thetank.
 7. The three-dimensional printing apparatus as claimed in claim 1,wherein the rotating shaft is disposed under the tank.